Image forming apparatus for weight property determination

Abstract

An image forming apparatus and method are disclosed. A detection light is radiated to a medium. An amount of transmitted light, an amount of regular reflected light, and an amount of diffuse reflected light are detected. A reflected-light-amount-equivalent value is obtained when the amount of regular reflected light is standardized based on the amount of diffuse reflected light. A glossy sheet-thickness coefficient is calculated by adding the reflected-light-amount-equivalent value to a transmitted-light-amount-equivalent value that is based on the amount of transmitted light. The weight property of the medium is determined, based on the glossy sheet-thickness coefficient, wherein the weight property comprises a basis weight or a thickness of the medium.

The invention claimed is: 
     
       1. An image forming apparatus comprising:
 an optical sensor comprising a light emitter to radiate light to a medium on which a toner image is formed, and a light receiver to detect an amount of transmitted light, an amount of regular reflected light, and an amount of diffuse reflected light; and 
 a processor to:
 calculate a glossy sheet-thickness coefficient by adding a reflected-light-amount-equivalent value to a transmitted-light-amount-equivalent value, wherein the reflected-light-amount-equivalent value is obtained when the amount of regular reflected light is standardized based on the amount of diffuse reflected light, and wherein the transmitted-light-amount-equivalent value is based on the amount of transmitted light, 
 determine a weight property of the medium based on the glossy sheet-thickness coefficient, wherein the weight property comprises a basis weight or a thickness of the medium, and 
 select a printing condition according to the weight property of the medium and perform a printing process using the selected printing condition. 
 
 
     
     
       2. The image forming apparatus according to  claim 1 , wherein the processor is to:
 determine an initial calibration-compensation coefficient based on a compensation table which correlates the initial calibration-compensation coefficient with light-emitting properties of the light emitter, and 
 calculate the reflected-light-amount-equivalent value based on the initial calibration-compensation coefficient and a value of the amount of regular reflected light that is standardized based on the amount of diffuse reflected light. 
 
     
     
       3. The image forming apparatus according to  claim 1 ,
 wherein the light receiver comprises a light-receiving sensor to detect the amount of transmitted light, the amount of regular reflected light, or the amount of diffuse reflected light, and 
 wherein the processor is to:
 receive a distance between the light emitter and the light-receiving sensor, 
 determine a conveying path width-compensation coefficient based on a compensation table which correlates the conveying path width-compensation coefficient with the distance between the light emitter and the light-receiving sensor, and 
 calculate the transmitted-light-amount-equivalent value based on the conveying path width-compensation coefficient and the amount of transmitted light. 
 
 
     
     
       4. The image forming apparatus according to  claim 1 ,
 wherein the light receiver comprises a light-receiving sensor to detect the amount of transmitted light, the amount of regular reflected light, or the amount of diffuse reflected light, and 
 wherein the processor is to calculate the glossy sheet-thickness coefficient with the following equation:
   Glossy sheet-thickness coefficient=(the amount of transmitted light{circumflex over ( )} Kgm )+ Ka {(the amount of regular reflected light/the amount of diffuse reflected light)−1}
 
 
 wherein, Kgm represents a conveying path width-compensation coefficient that is determined based on a distance between the light emitter and the light-receiving sensor, and Ka represents an initial calibration-compensation coefficient that is determined depending on light-emitting properties of the light emitter. 
 
     
     
       5. The image forming apparatus according to  claim 1 ,
 wherein the processor comprises processor readable instructions including glossy sheet-determination instructions to calculate a glossy sheet-determination coefficient by adding the reflected-light-amount-equivalent value to a regular reflected-light-amount-equivalent value, 
 wherein the reflected-light-amount-equivalent value is based on the amount of regular reflected light, and 
 wherein the glossy sheet-determination instructions comprise instructions to determine whether or not the medium is a glossy sheet based on the glossy sheet-determination coefficient. 
 
     
     
       6. The image forming apparatus according to  claim 5 ,
 wherein the processor is to determine an initial calibration-compensation coefficient based on a compensation table which correlates the initial calibration-compensation coefficient with light-emitting properties of the light emitter, and 
 wherein the glossy sheet-determination instructions comprise instructions to calculate the reflected-light-amount-equivalent value based on the initial calibration-compensation coefficient and a value of the amount of regular reflected light that is standardized based on the amount of diffuse reflected light. 
 
     
     
       7. The image forming apparatus according to  claim 5 ,
 wherein the light receiver comprises a light-receiving sensor to detect the amount of transmitted light, the amount of regular reflected light, or the amount of diffuse reflected light, 
 wherein the processor is to:
 receive a distance between the light emitter and the light-receiving sensor, and 
 determine a conveying path width-compensation coefficient based on a compensation table which correlates the conveying path width-compensation coefficient with the distance between the light emitter and the light-receiving sensor, and 
 
 wherein the glossy sheet-determination instructions comprise instructions to calculate the regular reflected-light-amount-equivalent value based on the conveying path width-compensation coefficient and the amount of regular reflected light. 
 
     
     
       8. The image forming apparatus according to  claim 5 ,
 wherein the light receiver comprises a light-receiving sensor to detect the amount of transmitted light, the amount of regular reflected light, or the amount of diffuse reflected light, and 
 wherein the glossy sheet-determination instructions comprise instructions to calculate the glossy sheet-determination coefficient with the following equation:
   Glossy sheet-determination coefficient=(the amount of regular reflected light{circumflex over ( )} Kgr )+ Ka {(the amount of regular reflected light/the amount of diffuse reflected light)−1}
 
 
 wherein, Kgr represents a conveying path width-compensation coefficient that is determined based on a distance between the light emitter and the light-receiving sensor, and Ka represents an initial calibration-compensation coefficient that is determined based on light-emitting properties of the light emitter. 
 
     
     
       9. The image forming apparatus according to  claim 5 ,
 wherein the processor-readable instructions include plain sheet-thickness determination instructions to calculate a compensated amount of transmitted light by standardizing the amount of transmitted light based on the amount of diffuse reflected light, to calculate a compensated amount of reflected light by standardizing the amount of regular reflected light based on the amount of diffuse reflected light, to calculate a plain sheet-thickness coefficient by adding the compensated amount of transmitted light to the compensated amount of reflected light, and to determine the basis weight or thickness of the medium based on the plain sheet-thickness coefficient, 
 wherein the glossy sheet-thickness determination instructions comprise instructions to determine the basis weight or thickness of the medium when the glossy sheet-determination instructions determine that the medium is a glossy sheet, and 
 wherein the plain sheet-thickness determination instructions comprise instructions to determine the basis weight or thickness of the medium when it is determined that the medium is a plain sheet. 
 
     
     
       10. The image forming apparatus according to  claim 9 ,
 wherein the processor is to determine an initial calibration-compensation coefficient based on a compensation table which correlates the initial calibration-compensation coefficient with light-emitting properties of the light emitter, and 
 wherein the plain sheet-thickness determination instructions comprise instructions to calculate the compensated amount of reflected light based on the initial calibration-compensation coefficient and a value of the amount of regular reflected light that is standardized based on the amount of diffuse reflected light. 
 
     
     
       11. The image forming apparatus according to  claim 9 ,
 wherein the light receiver comprises a light-receiving sensor to detect the amount of transmitted light, the amount of regular reflected light, or the amount of diffuse reflected light, 
 wherein the processor is to:
 receive a distance between the light emitter and the light-receiving sensor, and 
 determine a conveying path width-compensation coefficient based on a compensation table which correlates the conveying path width-compensation coefficient with the distance between the light emitter and the light-receiving sensor, and 
 
 wherein the plain sheet-thickness determination instructions comprise instructions to calculate the compensated amount of transmitted light by standardizing the amount of transmitted light based on the conveying path width-compensation coefficient and the amount of diffuse reflected light. 
 
     
     
       12. The image forming apparatus according to  claim 9 ,
 wherein the light receiver comprises a light-receiving sensor to detect the amount of transmitted light, the amount of regular reflected light, or the amount of diffuse reflected light, and 
 wherein the plain sheet-thickness determination instructions comprise instructions to calculate the plain sheet-thickness coefficient based on the following equation:
   Plain sheet-thickness coefficient=the amount of transmitted light/(the amount of diffuse reflected light{circumflex over ( )} Km )+ Ka {(the amount of regular reflected light/the amount of diffuse reflected light)−1}
 
 
 wherein, Km represents a conveying path width-compensation coefficient that is determined based on a distance between the light emitter and the light-receiving sensor, and Ka represents an initial calibration-compensation coefficient that is determined depending on light-emitting properties of the light emitter. 
 
     
     
       13. The image forming apparatus according to  claim 1 , wherein the optical sensor comprises a light-receiving sensor to:
 rotationally move around a measurement point as a center, which is an intersection point between an optical axis of the light emitter and the medium, in a measurement plane as a plane perpendicular to the medium and including the optical axis, 
 measure the amount of transmitted light at a regular transmission angle, 
 measure the amount of regular reflected light at a regular reflection angle, and 
 measure the amount of diffuse reflected light at a diffuse reflection angle. 
 
     
     
       14. The image forming apparatus according to  claim 1 ,
 wherein the optical sensor comprises a first light-receiving sensor and a second light-receiving sensor to rotationally move around a measurement point as a center, which is an intersection point between an optical axis of the light emitter and the medium, in a measurement plane as a plane perpendicular to the medium and including the optical axis, 
 wherein the first light-receiving sensor is to measure the amount of transmitted light at a regular transmission angle, and 
 wherein the second light-receiving sensor is to measure the amount of regular reflected light at a regular reflection angle, and to measure the amount of diffuse reflected light at a diffuse reflection angle. 
 
     
     
       15. The image forming apparatus according to  claim 1 , wherein the printing condition comprises at least one of a conveying speed, a transfer condition, or a fixing condition. 
     
     
       16. A method comprising:
 radiating detection light to a medium; 
 detecting an amount of transmitted light, an amount of regular reflected light, and an amount of diffuse reflected light; 
 receiving a reflected-light-amount-equivalent value when the amount of regular reflected light is standardized based on the amount of diffuse reflected light; 
 calculating a glossy sheet-thickness coefficient by adding the reflected-light-amount-equivalent value to a transmitted-light-amount-equivalent value that is based on the amount of transmitted light; 
 determining a weight property of the medium based on the glossy sheet-thickness coefficient, wherein the weight property comprises a basis weight or a thickness of the medium; 
 selecting a printing condition according to the weight property of the medium; and 
 performing a printing process using the selected printing condition. 
 
     
     
       17. The method of  claim 16 , wherein the printing condition comprises at least one of a conveying speed, a transfer condition, or a fixing condition. 
     
     
       18. An image forming apparatus comprising:
 an optical sensor comprising a light emitter to radiate light to a medium on which a toner image is formed, and a light receiver to detect an amount of transmitted light, an amount of regular reflected light, and an amount of diffuse reflected light; and 
 a processor to:
 calculate a glossy sheet-thickness coefficient by adding a reflected-light-amount-equivalent value to a transmitted-light-amount-equivalent value, wherein the reflected-light-amount-equivalent value is obtained when the amount of regular reflected light is standardized based on the amount of diffuse reflected light, and wherein the transmitted-light-amount-equivalent value is based on the amount of transmitted light, and 
 determine a weight property of the medium based on the glossy sheet-thickness coefficient, wherein the weight property comprises a basis weight or a thickness of the medium, 
 
 wherein the optical sensor comprises a light-receiving sensor to:
 rotationally move around a measurement point as a center, which is an intersection point between an optical axis of the light emitter and the medium, in a measurement plane as a plane perpendicular to the medium and including the optical axis, 
 measure the amount of transmitted light at a regular transmission angle, 
 measure the amount of regular reflected light at a regular reflection angle, and 
 measure the amount of diffuse reflected light at a diffuse reflection angle.